一方向に配向したSiCウイスカー/Al_2O_3複合材料の力学的性質

概要

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Uni-directionally oriented 20 vol%-SiC-whisker/Al_2O_3 composite (UD-comp) was fabricated by the sol-gel method from Al(OC_3H_7)_3 and by its extrusion. Mechanical properties of UD-comp were compared with those of 2-dimensional randomly oriented 20 vol%-SiC-whisker/Al_2O_3 composite (2DR-comp) made by conventional hot-press sintering. Fracture toughness K_<IC> value of UD-comp was measured to be 7.1 MPa・m^<1/2> which was larger than that of 2DR-comp (5.6 MPa・m^<1/2>). Improvement in fracture toughness by 2.3 times was realized over the fracture toughness K_<IC> 3.1 MPa・m^<1/2> of monolithic Al_2O_3 fabricated by the same sol-gel method. The same tendency was observed in effective fracture energy. These results indicate that whiskers aligned vertically to a crack were more effective than inclined whiskers for toughening by whisker bridging and pull-out. No increment in bending strength was obtained in UD-comp and its value was smaller than that of 2DR-comp. This result is attributable to the aligned direction of residual thermal stress.
社団法人日本セラミックス協会の論文
1992-11-01